It's pretty easy to resize a simple knitting pattern, and the skills you use are the same ones you will need to tackle more complex adjustments.
Easy Guide to Pattern Grading on Bluprint!
Mix & Match Sizing: Drop Sleeves - Victoria Marchant Knits
Easy Knitting Patterns for Beginners to Learn to Knit - Craft Evangelist
How to Resize a Dress
Easy Eyelet Yoke Sweater – Round 2 – Knittle and Pearl
Altering hand knits – a few suggestions – Fabrickated
Tutorial: Measuring the Upper Body of a Top-Down Sweater – Tamara Moots Designs
How to retrofit an FBA in a knit t-shirt
Easy Knits video tutorials: Make your first project with our new magazine
Easy DIY Turtleneck Bib Tutorial – No Knitting Required - The Last Stitch
How to Resize a Knitting Pattern?
Knitting A Garment at a Different Gauge – tin can knits
Understanding knitted fabric - a left- and right-handed knitting tutorial